We revalidate every domain approximately every four months and delist those which are no longer actively associated with malware.

However, we are some domains which we feel do not have to be re-certified that often. For example, there are 29 domains which were once on the dns-bh malware blacklist but were removed and are now relisted.

There are also several hundred domains which have been serving malware for over a year. We feel that these “repeat offenders” do not have to be checked as often as their only purpose seems to be for malware distribution.

Therefore, starting on the next update we will be using the second column of the domains.txt file to note these domains by including a “revalidation date” for these domains. (This column is currently empty.) That will give us more time to revalidate other domains instead of constantly checking these “immortal domains”.